1. Field of the Invention
This invention pertains generally to a copying apparatus, more specifically, to a paper loading mechanism for said copying apparatus.
2. Description of the Prior Art
A copying apparatus is a hard-copy unit used for making a hard-copy of an image displayed on a cathode ray tube (CRT) screen or of an image supplied from other image sources. A hard copy unit includes, in general, a fiber optic tube (FOT) and a roll of sensitized paper. A sensitized surface of the sensitized paper is pressed against a surface of the FOT and is moved in one direction as an electron beam generated within the FOT is periodically scanned in a direction perpendicular to said one direction while modulating a beam current or an intensity of said electron beam in response to an image signal. The sensitized paper is exposed to light, and is then heat developed as the paper passes through a processing section of said hard copy unit.
A typical example of a conventional hard copy unit is disclosed in U.S. Pat. No. 3,679,824 to Gibson Jr. and in U.S. Pat. No. 3,811,007 to Unger, both of the above patents being assigned to the assignee of the invention disclosed in this application. The processing section of the hard copy unit is disclosed in U.S. Pat. No. 3,864,709 to Bruns assigned to the assignee of the invention disclosed in this application. A prior art loading mechanism for loading the sensitized paper into the conventional hard-copy unit is disclosed in an instruction manual associated with Tektronix continuous recoder, model 4633A, and associated with video hard copy unit, model 4632.
The prior art paper loading mechanism associated with the conventional hard copy unit is illustrated in FIGS. 1A and 1B. FIG. 1A is a perspective view of the paper loading mechanism seen from the back or from the FOT side. FIG. 1B is a perspective view of an unlocked paper loading mechanism when loading or unloading a roll of the sensitized paper thereon. Such sensitized paper is mounted on a light shielded paper canister 10, the canister 10 being placed on a cassette assembly 12. The cassette assembly 12 includes cassette handles 14. Using cassette handles 14, the cassette assembly 12 will slide away from mainframe 16 and away from many other electrical and mechanical parts and components, including the FOT and its faceplate 18. When the cassette assembly 12 is positioned away from mainframe 16, an operator will have access to an expended canister 10 for removal thereof and will load a new paper canister 10 therein. Cassette assembly 12 further includes a paper locator 20 for engaging into a paper exit slot 22 on the canister 10, a paper roller 24, a paper guide 26, a knife assembly 28, a pin 30, and a fork 32. Although not shown in FIG. 1, a front cover is hinged at the bottom of mainframe 16 for known purposes.
For a better understanding of the conventional hard copy unit, reference is directed to FIG. 2 which illustrates a side cross sectional view thereof. The paper from the paper exit slot 22 of canister 10 is bent by a metal idler roller 24, by drive roller 36 mounted on mainframe 16, and by a pinch roller 38 mounted on cassette assembly 12. There exists, between idler roller 24 and drive roller 36, a faceplate 18 of the FOT and a foam pressure roller 34 which presses the paper against the faceplate 18. The paper further advances through a knife assembly 28, including a stationary blade 28a and a rotary blade 28b, through a processor assembly 40, including a processor belt 42, belt rollers 44 and a heating panel 46, around an ejector roller 48 adjacent a processor rear paper guide 50 and through a conveyor 52.
The following paper loading procedure is utilized by the conventional hard-copy unit:
1. Open the front cover. PA0 2. Push handles 14 down and pull out cassette assembly 12. PA0 3. Remove the expended canister 10, if any. PA0 4. Tear off the metallic light seal tape from the new paper canister 10 using the paper exit slot 22 and pull out approximately 12 inches of paper. PA0 5. Insert paper under metallic roller 24. PA0 6. Holding tension on paper canister 10, place it into the frame of a paper cassette assembly 12. Rotate the paper canister 10 until a locator 20 is engaged with paper exit slot 22 on paper canister 10. PA0 7. Pull a paper guide 26 forward. Thread paper up through knife assembly 28 and out the top of paper guide 26. Pull excess paper tight over the front of the unit. PA0 8. Push cassette assembly 12 in until it stops. Be sure that pin 30 is engaged by fork 32. PA0 9. Lift both handles 14 and lock firmly in place. PA0 10. Close the front cover.
This paper loading mechanism and the procedure utilized thereby is excessively complicated and is sometimes very dangerous to use as a result of the sharp knife edge of knife assembly 28, the knife edge sometimes injuring the operator during the paper loading process. In addition, improper paper loading often results in paper jams. Further, mechanical failures often result in system failure. As a result, frequent service calls are required.